Rolling mill for widening out tubes



April 11,1933.

`H. HEETKAMP ROLLING MILL FOR WIDENING OUT TUBES Filed May 27, 1951 ml]A'M wy/lm Wwf/M5 Attorney.

Patented Apr. 11, 1933 UNITED STATES PATENT 'or-*Fica HEINRICHHEETKAMROF DUISBURG, GERMANY, ASSIGNOB TU DEHAG AKTIENGESELL- SCHAFT, 0FDUISBURG, GERMANY I ROLLING MILL FOR WIDENING OUT TUBES I Applicationled Hay 27, 1981, Serial No. 540,428, and in Germany June 11., 1980.

It is known in connection with themanufacture of seamless tubes to passthe partly made tube, immediately after it leaves the tube rolling mill,through a -smoothing rolling mill, whereby the tube is not only smoothedbut is restored to its circular shape.

According t0 the present invention, a tube widening rolling mill. inwhich the partially prepared tube is forced over a conical mandrel headwith a rotary movement by means of inclined externally provided rollersand widened, is directly followed by a smoothing rolling mill comprisingrods or plugs and externally provided operating rollers, this mill beingin turn followed by a former lbush for bringing the tube back toitscircular shape, the former bush being providedto rotate more rapidlythan the tube. The smoothing rolling mill is employed solely forsmoothing the partially formed tube because the tubes, as they leave thewidening rolling mill, are scratched by the edges of the wideningrollers and the scratches must be removed. The tubes that have beensmoothed by this method are continuously guided in a heatedconditionthrough the former bush, so that tubes ready for use are produced by theuse, in co-operation, of the three apparatus here- `inbefore described.

4 Figure 1 shows the apparatus in longitudinal section,

Figure 2 is a section of the apparatus taken on the line 2-2`of Figure1,

Figure 3 is a section on the line 3-3 of Figure 1, and

Figures 4 and 5 are sections of the appa- 'ratus corresponding to Figure2, to illustrate modifications of construction.

In the drawing, 1 is a mandrel, provided with the conical mandrel head2.Within the head 2 are mounted conical rollersV 3, which loperate inconjunction with externally yprovided inclined mechanically drivenrollers 4. The front head 5, whichis connected to the head2, serves toguide in the partially prepared tube 6. Beyond the rollers 3 and 4 asmoothing rolling mill is provided, disposed in'the direction indicatedby the arrow w; th1s smoothin rolling mill comprises externally providedriven rollers 7 and a corre- .l spondmg number of ribs 8 upon themandrel 1. After the smoothing rolling mill a device 1s provldedconsisting of a rotatable funnelshaped former ring 9; this is providedat the end of a bush 10 mounted so as to be rotated by means of thechain wheel 11.

The plant operates as follows:

The partially formed tube which is inserted between the rollers 4 and 5,is flared out p at the end by the rollers until it becomes funnelshaped, and after the tube leaves theseV rollers it is in its flared outform forced over the ribs 8 with a rotary movement, where it is operatedupon internally and externally by means of the externally providedsmoothing rollers 7. This treatmentcauses the tube to lose its exactcircular sha e, and thus the tube, immediately after leavlng thesmoothing' apparatus, is passed into the funnelshaped rotating bush 10and is restored to its circular shape. The forming action of the ring 9upon the tube is considerably assisted,

yif the ring is rotated at a speed that exceeds the rotational speed ofthe tube as it moves past.

The apparatus is not limited to the construction illustrated. Thus theribs or parts 8 may be replaced by rollers 11, as represented in Figure4. Furthermore a rib 12 (Figure 5) in the form of a helix may beinternally provided in such manner that the pitch ofthe rib' changescontinuously. The effect of providing this helical rib is to cause thetube to move forward, this being particularly necessary after the tubehas left the flaringout rollers 3 and 4. The alteration in the pitch ofthe thread formed by the rib prevents helical scratches in the tube frombein .exposed. The finished tubeleaves the widening-out rolling mill atthe end of the bush.

I claim:

1. A tube widening mill provided with a mandrel with conical head,externally disposed inclined rollers co-operating with said rolls, ands, former bush following the smoothing rolls, which bush is rotatedaround the tube with a relative speed.

2. A tube widening mill according to claim 5 1, in which said means isprovided with ribs disposed within the tubo to co-operate with thesmoothing rolls.

3. A tube widening mill according to claim 1, in which said means isprovided with a helical rib Within the tube to co-operate with thesinoothing rolls.

HEINRICH HEETKAMP.

